Tubular fabric.



C. S. SMITH.

TUBULAR FABRIC.

APPLICATION FILED AUG. 1, 1911.

1 ,01 6,527'. Patented Feb. 6, 1912.

UNITED STATES PATENT OFFICE.

CHARLES S. SMITH, OF PROVIDENCEnR-HODZE ISLAND, ASSIG-NOB TO CHERNACK MANU- FACTURIN G COMPANY, OF PAWTUCKET, RHODEl ISLAND, A CORPORATION OF RHODE ISLAND.

TUBULAR FABRIC.

Specication of Letters Patent.

"Application led August 1, 1911.

Patented Feb. 6, 1912.

serial No. 641,816.

citizen of the United States, and a resident 'of Providence, in the county of Providence and State of Rhode Island, have invented certain new and useful Improvements in Tubular Fabrics, of which' the following is a specification.

The present invention relates to tubular Woven fabric such as that commonly used for insulating electric conductors.

The object of the invention is to provide a tubular woven fabric of such material, and with the strands of such form and in such relationship, that the conduit will meet all underwriters requirements when vemployed for containing electric conductors.

Of the accompanying drawings, which illustrate one formin which the present invention may be. embodied,-Figure 1 represents a longitudinal elevation, partly in section, `on a comparatively largelscale, of a piece of tubular woven fabric, the weave eing shown loose or open to better illustrate the manner in which the article is made. Fig. 2 represents an elevation of a strand composed of a plurality of strips twisted together.v Fig. 3 represents an elevation of a strand consisting of a single strip which is twisted. Fig. 4 represents an elevation of a strip in its lncipient stage of being crumpled to form a strand like that shown in Fig. 3. Fig. 5 is a view similar to a portion of Fig. 1 but illustrating the closeness of the weave as actually made. The same reference characters indicate the same parts wherever they occur.

The tubular fabric, as represented by Fig. 1, is woven, as distinguished from braided; that is to sa it comprises longitudinal strands and helical strands, the strands '10 being vcomparatively soft and flexible and the strands 11 being comparatively hard and' stiff. According to the arrangement shown, the soft strands 10 constitute the warp, and the hard strands 11 constitute the weft or filling. The manner of weaving the` strands 10 and '11 forms no part of the present invention, the invention residing wholly in the article illustrated in Fig. 5.

Referring to Fig. 2, the strand 11 shown thereby isl composed of a plurality of strips 12 crumpled laterally and twisted together to make the strand circular in cross section .and thick and comparatively hard and stili?.

The strips 12 may be made of any suitable sheet material, such as thin paper, and .when more than one is used for a strand, they are preferably laid in layers before being crumpled and twisted.

The tubular fabric represented by Fig. 1 comprises two hard-twisted helical weft or filling strands, each of which is made in the manner shown by Fig. 2. The warp strands 10 may be made of 'cotton or any other suitable material, but, while the strands 11 are thick and comparatively hard and stiff for the purpose of lending rmness, the strands 10 are preferably soft' and comparatively flexible for the purpose of facilitating the weaving operation and to secure a close tight weave.

The structure shown, while imparting all the necessary strength against pressure, allows enough longitudinal flexibility to permit the conduit to be led and laid wherever required, because the portions of the relatively soft material of the strands 10 where they cross each other between the strands or coils 11 of harder material, will yield to permit the coils to approach each other along the concave side of the curve in which the conduit is being laid, and to correspondingly open along the convex side of that curve. And this occurs without any such interruption of the close nature of the weave as to ever necessitate an extra wall or covering.

I do not wish to be limited to the number of strands shown, for whereas Fig. 1 illustrates tubular fabric having two weft strands 1l, similar fabric might be made by using one or any number of helical weft strands. f.

' The strand 11c represented by Fig. Consists of one strip instead of a plurality of twisted strips twisted together. This form of strand, although somewhat different from the form shown by Fig. 2, is nevertheless adapted to be used in the same manner and with the4 same result. The tubular fabric may be saturated or coated with any suitable compound for rendering it waterproof Vor noncombustible, or if desired, the compound may be administered to the strands prior to the weaving operation. The fabric may be used for a conduit or covering or for any other purpose. The circular cross section of the weft resulting from the twist- Y 'ing of the thin material imparts sutliclent rigidityr to the article to resist distortion due to crushing strain, and further permits such close weaving of the warp and weft that tion.4 When the strands 10 are closely interwoven therewith, the tubular article needs no additional outer wall or shell, be-

cause the hardness of the strands 11, andtheir transverse circular formation, imparts all necessary rigidity to the tube to resist distortion due tothe crushing strain. In

this respect my improved tubular fabric differs materially from one having flat or nearly fiat weft or filling strands, the shape of which is such as to preclude the tube from having much strength unless such strands. are made of metal which latter would of course be objectionable if the tube -is to be used as a conduit for electric conductors.

By the term hard-twisted, I mean that the thin material which comprises the strands 11 is twisted to a suilicient degree of tightness to make the said strands so hard that they will be quite rigid, and will preserve l the -form of the strands 10 with no striaght portions but having a'y series of continuous uniform in-and-out curves, the inner curves being equal to the outer curves, whereby the 4 complete tubular fabric is rendered exceedingly strong and rigid without the employment of any outer shell. The longitudinal strands 10 have equal alternating interior and exterior curves which substantially describe sexni-circles and closely fit the exterior of the@ helical strands 11. And the helical strands areheld firmly against lateral movements. Furthermore, the crossing portions of adjacent longitudinal strands are gripped so tightly by the helical strands .that a tight structure is formed and one that resists collapsing due toexternal pressure.l

At the same timeV this provides suiiicient flexibility for the purpose of conduits forelectric conductors.

I claim 1. A tubular fabric comprising longitudi-4 nal strands, and a helical twisted strand substantially circular in cross section closely interwoven with the longitudinal strands, said helical strand being composed of thin paper, the twisting of the thin material renderin it thick and comparatively hard and sti and capable of providing the necessary rgidty without an additional outer wall or she l.

2. A tubular fabric adapted for use as' a conduit for electric conductors, said fabric comprising longitudinal and helical strands, the latter being of hard-twisted paper, the said longitudinal and helical strandsbeing tightly interwoven whereby a strong tube having a wall of a single thickness 1s provided.

In testimony whereof I have aiiixed my signature, in presence of two witnesses.

CHARLES S. SMITH.

Witnesses C. F. BROWN, P. W. PEzzETrI. 

